Does Articular Disc Position Change Following Mandibular Setback Surgery?

BACKGROUND: Maintaining condyle position following bilateral sagittal split ramus osteotomy (BSSO) is crucial to minimizing postoperative relapse. However, the impact of BSSO on the articular disc position remains inconclusive. PURPOSE: This study aimed to investigate the changes in articular disc position following setback BSSO surgery. STUDY DESIGN, SETTING, AND SAMPLING: In this prospective cohort study, subjects with mandibular prognathism requiring setback BSSO were enrolled between August 2021 and June 2022 at the Oral and Maxillofacial Surgery Clinic, Faculty of Dentistry, Chiang Mai University, Thailand. Patients with surgical complications, loss of follow-up, or significant artifacts in their MR images were excluded. PREDICTOR/EXPOSURE/INDEPENDENT VARIABLES: The predictor variable was time. The articular disc position was assessed at 3 time points, preoperatively (T0), 3 months postsurgery (T1), and 6 months postsurgery (T2). MAIN OUTCOME: The primary and secondary outcome variables were the changes in articular disc position between T0-T2 and T0-T1, respectively. Articular disc position was coded as normal, anterior disc displacement with reduction (ADDwR), anterior disc displacement without reduction (ADDwoR), and anterior disc displacement without reduction and degenerative joint disease (ADDwoR + DJD). COVARIATES: Covariate variables collected included age (years), sex (male or female), asymmetry (present or absent), surgical procedure (single jaw (BSSO) or bimaxillary surgery), and setback distance (millimeters). ANALYSES: Friedman's test with 80% power and a significance level of 0.05 was employed. Pairwise comparisons were performed using the Dunn-Bonferroni posthoc test to identify statistically significant differences. RESULTS: The study included 16 subjects, 6 females and 10 males, with a total of 32 TMJs. Subjects had a mean age of 23.75 (4.57) years. The proportion of TMJs with normal disc position postoperatively increased from 3 (9.4%) to 19 (59.4%). Statistically significant differences were found in the changes in disc position over time (P < .001). CONCLUSIONS: Following setback BSSO, the articular discs underwent changes, with a majority of ADDwR cases transitioning to a normal position. Cases with ADDwoR also demonstrated disc reduction capability after surgery. The combined orthodontic treatment and setback BSSO appear to have an effect on articular disc position in skeleton class III patients.

Association between hepatitis C infection in Thai patients with oral lichen planus: A case-control study.

AIM: The aim of the present study was to investigate the prevalence of hepatitis C virus (HCV) infection and evaluate liver enzyme levels in patients from upper northern Thailand with oral lichen planus (OLP). METHODS: A case-control study of 101 patients with OLP and 101 patients without OLP was conducted. Peripheral blood was taken from each patient and screened for anti-HCV antibody using immunochromatography. Positive samples were further confirmed using chemiluminescent microparticle immunoassay (CMIA) and reverse transcription-polymerase chain reaction. In addition, liver enzyme levels, alanine transaminase, aspartate transaminase, and alkaline phosphatase were evaluated using spectrophotometry. RESULTS: Immunochromatography and CMIA revealed that nine patients with OLP (8.9%) were positive for anti-HCV antibodies, whereas only one patient without OLP was HCV positive (odds ratio = 9.78). All patients who were HCV positive had significantly higher liver enzyme levels than patients who were HCV negative. CONCLUSIONS: The results of the present study indicated that OLP in certain patients was significantly associated with HCV. This could warrant screening for HCV-infected patients with OLP in Thailand.